article <370vcl$onl at mserv1.dl.ac.uk>, grggta at picr.cr.man.ac.uk (Graham Atherton) writes:
>We are beginning to use luciferase as an internal control for CAT assays.
>We find that the levels of luciferase activity varies up to 2x between
>replicates (ie two independant plates of cells which receive half each
>of the same CaPO4/DNA ppt) and up to 20x between samples (ie ppt's
>containing different DNA's). This level of variation is far higher than
>when we used other reporter genes as internal control - is it likely to
>be a genuine measure of DNA uptake? These levels of variation seem
>very high to us.
>Graham Atherton
>grggta at picr.cr.man.ac.uk
Graham.
This does seem like an unacceptable variation.
Have you tried lacZ? Our experience is that lacz results have been quite
quantitative, at least in yeast an mammalian cells.